The proposed project has two objectives which will be implemented in three African countries (Uganda, DRC, and Ethiopia) which are endemic for onchocerciasis. The proposed project for Objective 1 will seek to measure the impact of onchocerciasis control and elimination programs. More specifically we seek to evaluate the evolution of biomarkers of onchocercial infection as mass drug administration (MDA) progresses, and to evaluate the performance of diagnostic tools for onchocercial infection in areas that are approaching the interruption of transmission. Recruitment of respondents into the study will be via convenience sampling. For Objective 1 we seek to recruit 1,500 participants, and for the second objective, 3000 participants, in conformance with the instructions in the request for proposals. Participants will be subjected to physical, oral and serologic examinations. Information generated from collected data will serve to inform policy makers so as to effectively promote and strengthen NTD elimination efforts. The project for Objective 2 seeks to measure the impact of onchocerciasis control and elimination programs using mass drug administration (MDA) on coendemic lymphatic filariasis (LF). More specifically the project seeks to develop a standardized protocol to evaluate the status of LF in the areas of onchocerciasis and LF overlap; evaluate the impact of mass drug administration of ivermectin for the control of onchocerciasis on reducing the prevalence and transmission of lymphatic filariasis (LF); and in LF implementation units (district), compare prevalence of LF between communities that have received ivermectin MDA with those that have not received it. Recruitment of respondents into the study will be via convenience sampling in the selected implementation units. Physical, oral and serologic and microscopic examinations will be performed on respondents. Information generated from collected data will serve to inform policy makers so as to effectively promote and strengthen NTD elimination efforts, with a possibility of calling for integration of onchocerciasis and LF.